Simplified oil refinery



Cim/entor- I' @Z225 E $5.5

mter H. J2 UPP (lister-neg United States Pared-t SIMPLIFIED on. REFINERY Walter H. Rupp, Mountainside, N. J., assignor to Esso Research and Engineering Company, a corporation of Delaware Application September 18, 1952, Serial N0. 310,193

1 Claim. (Cl. 19a-4s) The present invention is concerned with an improved integrated method for the processing of petroleum oils. The invention is more particularly concerned with an operation wherein crude oil is separated into a plurality of fractions, in the presence of cracked products from one or more of these fractions to produce virgin and cracked products in the boiling range from gasoline to fuel oil. In accordance with the present invention the crude oil is used as a primary absorption medium and is supplemented by recycling catalytic gas oils.

It is well known to process crude oils by separating them into a plurality of fractions and processing each of said fractions separately. In such cases virgin and cracked fractions are fractionated or distilled in separate distillation zones and the products blended as desired. However, this results in duplication of equipment and tremendously increases the cost and space of any plant which attempts to carry all of these operations in one setting.

It is therefore the main object of this invention to combine distillation, cracking, product blending and light ends recovery in a single simplified operation.

It is a further object of this invention to integrate retinery operations in a single compact unit wherein investment and operating costs are lowered, and required floor space, piping and utilities are reduced.

These and other objects of this invention are accom plished by introducing a crude oil into the top of a fractionating zone wherein both cracked and virgin i. e. uncracked products are being distilled. The crude oil is passed countercurrent to the rising vapors produced by the distillation of the cracked and virgin oils. A side stream comprising virgin fat oil containing absorbed constituentsis withdrawn from the upper part of the fractionating zone and reintroduced into the bottom of the fractionating Zone where it is distilled to produce both virgin and cracked vapors, the cracked vapors being obtained from the vaporization of the cracked constituents absorbed by the crude oil. A heavy virgin gas oil fraction is withdrawn from a point near the bottom of the fractonating zone but above the point at which the side stream is reintroduced into the fractionating zone. This heavy gas oil fraction is subjected to a conventional cracking operation to produce cracked products which are returned to the fractionating zone at a point above the point at which the heavy virgin gas oil fraction is withdrawn. Various conventional side streams may be withdrawn from the fractionating zone as desired. Unabsorbed gas is withdrawn overhead and residual fuel oil is withdrawn from the bottom of the tower.

In a preferred modification the heavy gas oil fraction is cracked in the presence of a powdered uidized catalyst and the cracked products together with entrainment catalyst are returned to the fractionating Zone. These products undergo fractionation with vapors and residue. The residue contains the residual catalyst and is Withdrawn and settled to obtain a clarified oil and a slurry of catalyst in oil. The slurry is added to the heavy gas oil fraction being 2,733,191 Patented Jan. 31, 19756 ICC fed to the catalytic cracking reaction and the clarified oil is added to the fuel oil product withdrawn from the bottom of the tower.

If desired a heavy gas oil fraction may be withdrawn from a point near the middle of the fractionating zone and reintroduced into the top thereof as reflux. f

The present invention may be readily understood by reference to the drawing illustrating one embodiment of the same. Feed crude oil is introduced cold, i. e. at room temperature, into the top of fractionating zone 10 by means of line 1 wherein it is contacted with gases and highly heated vapors rising through the tower. `Zone 10 is provided with suitable bubble cap plates or their equivalent and suitable contacting and distributing means and with a plurality of trap-out trays 36, 37, 38, 39, 40, 41 and 42.

Temperature and pressure conditions and other operating conditions in zone 10 are adjusted so as to absorb in the crude oil hydrocarbon constituents containing three and more carbon atoms in the molecule. Preferred conditions are 60-100 F. for crude oil entering in line 1 and 1GO-200 F. for fat oil leaving through line 6. Pressures in tower 10 are preferably maintained at 5-15 p. s. i. g.

A low pressure fuel gas yfree of hydrocarbons having more than two to three carbon atoms per molecule is removed overhead from zone 10 by means of line 2 and handled in any manner desired. The rich absorption oil ows downwardly in zone 10l and the temperature of the same may be controlled by means of external heat exchangers 3 through which the liquid is circulated from zone 10 by means of lines 4 and 5. Crude fat oil is collected on trap-out tray 36, withdrawn from zone 10 by means of line 6 and passed through exchanger 7 which consists of a unit wherein there exists a fluidized bed of solids outside of tubes which contain the crude fat oil. Hot flue gas or other uidizing medium is introduced into the iluidized bed of solids in exchanger 7 by line 8. This gas is introduced at such a rate that the bed of solids is maintained as a pseudo liquid. The gas leaves the exchanger 7 by means of line 9 and is introduced into regenerator 15 as described below.

The oil stream is withdrawn from exchanger 7 by means of line 11 at a temperature of 700-1000 F. and re-introduced into the bottom of tower 10. In this section of the tower the crude fat oil is separated into vapors and liquid residue, the vapors passing upwardly through the tower around baille plates, bubble caps, trap-out trays, and similar devices through the various sections of the tower where they undergo fractionation in the well known manner. Reflux condensate collects at various points in the tower and is drawn off as described below.

A heavy gas oil cut is collected on trap-out tray 42 and passes from zone 10 by means of line 13 to catalytic reactor 12 at a temperature of SOO-800 F. where it is subjected to cracking conditions in the presence of a fluidized catalyst. Fluidized catalyst is withdrawn from the bottom of reactor 12 by means of line 14 at a temperature of 80G- 1000" F. and passed into regeneration zone 15. Flue gas is withdrawn from zone 15 by means of line 16 at a temperature of 1000-l200 F. The regenerated catalyst is withdrawn by means of line 17 and recycled to the catalytic reactor 12 through line 48. Air for regeneration of catalyst is provided through line 49. Cracked products and entrained catalyst are withdrawn from reactor 12 by means of line 18 at a temperature of 900-1000 F. and introduced into tower 10 below trap-out tray 38. The oil and entrained catalyst contacts vapors rising from below trap-out tray 39 and is separated into vapors and residue. The vapors pass on up the tower through trap-out tray 38 while the residue and catalyst are collected on plate 39 which is withdrawn by line 19 into settler 20 where the mixture of oil and catalyst separates into an upper layer 3 of claried oil and a lower layer of catalyst-oil slurry. The claried oil is withdrawn by line 21 and combined with residual oil drawn from the bottom of the tower by line 22. The catalyst slurry is withdrawn from settler 2t) by line 23 and combined with the heavyV gas oil to cracking in line 13.

The cracked and virgin vapors passing up the tower through plate 33 are fractionated into a plurality of mixed cracked and virgin fractions. Thus a light gas oil fraction is collected on plate 37 and withdrawn through line 24. A heavy gas oil fraction is collected on tray 38 and either passed by line 25 to reactor 12 for further cracking or is withdrawn through line 26.

Similarly a light virgin gas oil fraction is collected on tray 41 and withdrawn through line 27. A heavy virgin gas oil may also be withdrawn through line 28 from trapout tray 42.

In accordance with an alternative adaptation of the invention a stream is withdrawn from zone 10 and trap-out tray 38 by means of line 29 passed through cooler 30 and reintroduced into the top of zone 10 at 60-100 F. as reiluX therein. A vapor side stream is withdrawn from zone 10 by means of line 31 passed through compressing zone 32 and introduced into stabilization zone 33. Temperature and pressure conditions are adjusted in zone 33 to remove overhead, by means of line 34, a stream com prising constituents having 3 and 4 carbon atoms in the molecule. A stream comprising virgin and cracked hydrocarbon constituents is withdrawn from the bottom of zone 33 by means of line 35.

The foregoing description does not by any means cover the possible uses of this invention nor the forms which it may assume, but serves to illustrate its fundamental principles and an assembly in which the novel features as disclosed above have been incorporated. It is obvious that changes in the details may be made without departing from either its novel characteristics or the spirit and scope of this invention as dened in the appended claim.

The nature and objects of the present invention having been thus described and illustrated, what is claimed as new and useful and is desired to be secured by Letters Patent is:

Unitary process for preparing cracked and non-cracked products from crude oil which comprises introducing a crude oil into the top of a fractionating zone, wherein both cracked and non-cracked oils are being distilled, passing the oil counter-current to rising vapors of the cracked and non-cracked oils being distilled, withdrawing from the upper part of the fractionating zone a side stream comprising non-cracked fat oil containing absorbed constituents, heating and reintroducing the said withdrawn material into the bottom of said fractionating zone where it is subjected to distillation conditions to produce noncracked and cracked vapors which pass up the fractionating zone, withdrawing a heavy gas oil fraction comprising a preponderance of uncracked products from near the bottom of the fractionating zone but above the point at which the said withdrawn products are reintroduced, subjecting the heavy gas oil fraction to cracking conditions in the presence of a powdered fluidized catalyst to produce cracked products containing small amounts of entrained catalyst, introducing the cracked products and the entrained catalyst to the fractionating zone at a point above the point at which said heavy gas oil fraction is withdrawn, subjecting the cracked products to fractionating conditions within the fractionating zone to produce vapors and a residue containing the entrainecl catalyst, withdrawing the residue and entrained catalyst from an intermediate point in the fractionating zone below the point at which the cracked products were introduced, separating the residue into an upper layer of clarified oil and a lower layer of catalyst oil-slurry, combining the lower layer of catalyst oil-slurry with the said heavy gas oil fraction prior to subjecting it to said catalytic cracking, withdrawing unabsorbed gas overhead from said tower, withdrawing residual fuel oil from the bottom of said tower and combining it with the said clarified oil as the fuel oil product.

References Cited in the le of this patent UNITED STATES PATENTS 2,174,858 Keith Oct. 3, 1939 2,294,126 Ocon Aug. 25, 1942 2,414,883 Martin Jan. 28, 1947 2,447,149 Wier Aug. 17, 1948 

